Toba's erupted mass deposited an ash layer of about 15 centimetres (6 in) thick over the Indian subcontinent. The eruption was of exceptional intensity and was completed within only 9 to 14 days. The Toba eruption was the largest explosive volcanic eruption known in the Quaternary period. An even larger volume of 6,000 km 3 (1,400 cu mi) DRE has been suggested based on lost and eroded ash from pyroclastic flows. Computational ash dispersal models suggested possibly as much as 5,300 km 3 (1,300 cu mi) DRE was erupted. īased on known distribution of ash fall and pyroclastic flows, eruptive volume was estimated to be at least 2,800 km 3 (670 cu mi) dense-rock equivalent (DRE), of which 800 km 3 (190 cu mi) was deposited as ash fall. It had an estimated Volcanic explosivity index (VEI) of 8 (the highest rating on the scale) it made a sizable contribution to the 100 km × 35 km (62 mi × 22 mi) caldera complex. This eruption was the last and largest of four eruptions of the Toba Caldera Complex during the Quaternary period, and is also recognized from its diagnostic horizon of ashfall, the Toba tuff. The Toba eruption occurred at the present location of Lake Toba in Indonesia and was dated to 73,880 ± 320 years ago through high-precision potassium argon dating. See also: List of large volcanic eruptions However, some physical evidence disputes the links with millennium-long cold event and genetic bottleneck, and some consider the theory disproven. Ambrose of the University of Illinois Urbana-Champaign. In 1998, the bottleneck theory was further developed by anthropologist Stanley H. Rampino of New York University and volcanologist Stephen Self of the University of Hawaiʻi at Mānoa supported her suggestion. Science journalist Ann Gibbons posited that the low population size was caused by the Toba eruption. Ī number of genetic studies revealed that 50,000 years ago human ancestor population greatly expanded from only a few thousand individuals. The Toba catastrophe theory holds that this event caused a severe global volcanic winter of six to ten years and contributed to a 1,000-year-long cooling episode, leading to a genetic bottleneck in humans. It is one of the Earth's largest known explosive eruptions. The Toba eruption, (sometimes called the Toba supereruption or the Youngest Toba eruption) was a supervolcano eruption that occurred around 74,000 years ago at the site of present-day Lake Toba in Sumatra, Indonesia.
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